I have upgraded my wii to the latest version now the homebrew wont work

before i start please escuse my ignarance as i am not especially good with computers!

i have been using an SD card and HDD connected to my wii for approx 4 years. i recenetly purchased a new wii game which wouldnt work so i was advised to upgrade my wii. when i was 'given' the attachment to allow extra games to be played i was advised to disconnect my wii from the internet so upgrades were not allowed.i reconnected my connection last night which upgraded my wii to the latest version so now the new game works but when i switch on my wii it goes directly to the wii front page rather than directly to the usb loaded page (i think that is what it is called)i have looked at the sd card and all of the files are sill there. (nand.bin, boot.elf, bootmii, apps, private etc but it wont work when i switch on my wii.i am presuming i need to upgrade something on the SD card but i would really appreciate if someone can help point me in the right direction in as simple way as possible as i am a bit stupid. i have looked through the forum and cant find anything that seems to get me out of the mess i am in and probably created myself)hope someone can help